The Complete Guide to Image Format Conversion

I spent the better part of last Tuesday converting 1,200 product images from HEIC to JPEG. Not because I wanted to, obviously, but because the client’s photography team had just upgraded to new iPhones, shot everything in HEIC, and then discovered that their e-commerce platform couldn’t display a single one of them. Twelve hundred images. All perfect. All useless in the wrong format.

That’s the thing about image formats — they seem like a trivial detail until they’re the only thing standing between you and a working website. You can take the most stunning photograph in the world, but if it’s trapped in a format that your audience’s browser can’t render or your CMS won’t accept, it might as well not exist.

This guide is the one I wish I’d had back when I first started dealing with format headaches. We’ll cover every major image format, when you’d actually want to use each one, how to convert between them without destroying your images, and how to do it all at scale without losing your mind.

The Format Landscape: A Field Guide to Every Format That Matters

There are dozens of image formats floating around, but in practice, you’ll deal with about eight of them regularly. Here’s the honest breakdown — not the textbook definition, but what each format actually means for your day-to-day work.

Format	Type	Transparency	Animation	Best For	Watch Out For
JPEG/JPG	Lossy	No	No	Photos, web images	Quality degrades on re-save
PNG	Lossless	Yes	No	Graphics, logos, screenshots	Huge files for photos
WebP	Both	Yes	Yes	Modern web delivery	Older software compatibility
GIF	Lossless (256 colors)	Yes (1-bit)	Yes	Simple animations, memes	Limited to 256 colors
HEIC/HEIF	Lossy	Yes	Yes	iPhone/iPad photos	Almost nothing outside Apple reads it natively
TIFF	Both	Yes	No	Print, archival, professional editing	Massive file sizes
BMP	Uncompressed	Limited	No	Legacy Windows applications	Absurdly large files
AVIF	Both	Yes	Yes	Next-gen web delivery	Slow encoding, newer browser support

JPEG is the cockroach of image formats — I mean that as a compliment. It’s survived since 1992, works literally everywhere, and handles photographs reasonably well. Its weakness? Every time you open a JPEG, edit it, and save it, it loses a tiny bit more quality. It’s like making a photocopy of a photocopy. Do it enough times and things get ugly.

PNG is what you reach for when you need pixel-perfect accuracy or transparent backgrounds. Logos, icons, screenshots with text, UI mockups — PNG handles all of these beautifully. Just don’t try to use it for photographs, because a single PNG photo can easily hit 10-15 MB. For a broader overview of when these formats shine, check out our image file formats guide.

WebP is Google’s answer to “what if JPEG and PNG had a baby that was better than both of them?” It delivers smaller files, supports transparency and animation, and has near-universal browser support. More on that later.

GIF is ancient, limited to 256 colors, and technically inferior to almost every other format. And yet it refuses to die, because nothing else has quite nailed the “shareable short animation” use case the same way. If you’re working with GIF files regularly, our GIF format guide dives much deeper.

HEIC is Apple’s preferred format for iPhone photos since iOS 11. It’s genuinely excellent — roughly half the file size of JPEG with better quality. The problem? Try opening an HEIC file on a Windows PC from 2019, uploading it to a website, or sending it to anyone without an Apple device. Suddenly “excellent” becomes “completely useless.” We’ve got a full HEIC to JPG conversion guide that covers every workaround.

TIFF is the format professionals trust for print work and archival storage. It preserves every last detail, supports layers and multiple pages, and works beautifully with professional design software. The trade-off is enormous file sizes — a single TIFF from a 50-megapixel camera can easily exceed 100 MB. Our TIFF format guide explains when that trade-off is worth it.

BMP is the digital equivalent of a landline phone. It’s uncompressed, it’s enormous, and it’s almost exclusively a legacy Windows artifact at this point. But legacy systems and certain industrial applications still require it, so it’s worth knowing about. Check out our BMP conversion guide if you’ve found yourself stuck with BMP files.

AVIF is the new kid that’s genuinely impressive. We’ll talk about it more later, but the short version: 50% smaller than JPEG at the same visual quality. That’s not marketing fluff — it’s measurable. For a deep dive into how AVIF stacks up against other next-gen formats, read our HEIF and AVIF formats comparison.

Lossy vs Lossless: The Decision That Shapes Everything

Before you convert a single file, you need to understand the fundamental split in how image formats handle data. Get this wrong and you’ll either bloat your storage with unnecessarily huge files or destroy image quality without even realizing it.

Lossy compression throws away data to make files smaller. The clever part is that it targets data your eyes won’t miss — subtle color variations, fine texture details, imperceptible gradients. At reasonable quality settings (75-85%), the difference between the original and the compressed version is invisible to virtually everyone. Go below 60% and you start seeing blocky artifacts, color banding, and that unmistakable “compressed too hard” look.

Lossless compression keeps everything. Every pixel, every color value, every last bit of data survives the compression. The file gets smaller through clever encoding — think of it like zip compression for images — but nothing is ever discarded. The downside? Lossless typically achieves 10-40% reduction compared to lossy’s 50-80%.

Here’s the part that trips people up: converting from a lossy format to a lossless format doesn’t recover lost data. If you take a JPEG that’s already been compressed to 70% quality and convert it to PNG, you get a much larger file that’s pixel-identical to the compressed JPEG. You’ve gained file size without gaining quality. It’s like scanning a photocopy at high resolution — the copy’s imperfections are now preserved in exquisite detail.

The practical rule is straightforward: always keep your highest-quality source file. Edit and archive in lossless formats (PNG, TIFF). Export to lossy formats (JPEG, WebP) as the final step for delivery. And never, ever convert from lossy to lossy to lossy in a chain — each step degrades quality further.

For a thorough comparison of how these compression types play out across real-world scenarios, see our WebP vs JPEG vs PNG compression comparison.

When Your Camera’s Default Format Isn’t Good Enough

Cameras and phones make format decisions for you, and those decisions aren’t always great. Here are the scenarios where conversion isn’t optional — it’s necessary.

The iPhone HEIC Problem

Every modern iPhone shoots in HEIC by default. Apple made this choice because HEIC produces smaller files with better quality than JPEG — a genuinely smart engineering decision. But the moment those photos leave the Apple ecosystem, problems start. Your WordPress site won’t display them. Your client’s Amazon listing rejects them. The print shop can’t open them. The social media scheduling tool you use doesn’t recognize them.

The fix is straightforward: batch convert your HEIC files to JPEG or WebP. You can do this right in your browser with BulkImagePro’s HEIC to JPG converter. No software to install, no quality loss beyond the initial conversion, and it handles hundreds of files at once.

The DSLR RAW Workflow

Professional cameras shoot in RAW formats (CR2, NEF, ARW — every manufacturer has their own). RAW files give you maximum editing flexibility, but they’re enormous (25-60 MB each) and can’t be displayed on the web or shared directly. The standard workflow is to edit in RAW, then export to JPEG or TIFF for delivery.

The “Wrong Format for the Job” Problem

I see this constantly: someone saves a photograph as PNG (producing a 15 MB file that should be a 300 KB JPEG), or saves a logo as JPEG (introducing compression artifacts around sharp text edges). Using the wrong format doesn’t just waste bandwidth — it can visibly degrade your images.

The Legacy System Migration

Maybe you’ve inherited a website with 10,000 BMP files from 2004. Maybe your company’s document management system exported everything as TIFF. Maybe you’re migrating to a platform that only accepts JPEG, PNG, and WebP. In all of these cases, batch format conversion is the bridge between where you are and where you need to be.

What Actually Works on the Web (And What Doesn’t)

Browser compatibility is the ultimate arbiter of which formats you can use on the web. You might fall in love with AVIF’s compression efficiency, but if a meaningful slice of your audience can’t see the images, that efficiency doesn’t matter.

Here’s the current state of browser support as of early 2026:

Format	Chrome	Firefox	Safari	Edge	Global Support
JPEG	All versions	All versions	All versions	All versions	~100%
PNG	All versions	All versions	All versions	All versions	~100%
GIF	All versions	All versions	All versions	All versions	~100%
WebP	32+ (2014)	65+ (2019)	16+ (2022)	18+ (2014)	~97%
AVIF	85+ (2020)	93+ (2021)	16.4+ (2023)	121+ (2024)	~93%
HEIC	No	No	Yes (macOS only)	No	~15%
TIFF	No	No	Yes (partial)	No	~15%
BMP	Yes	Yes	Yes	Yes	~97% (but why?)

A few things jump out from this table. JPEG and PNG remain the only truly universal formats. WebP has crossed the threshold where you can use it as your primary format and only worry about the remaining ~3% if your audience skews toward very old devices. AVIF is closing in fast, but the ~7% gap still matters for high-traffic commercial sites. And HEIC has essentially zero web support outside of Safari on macOS — which is exactly why conversion matters so much.

The <picture> element lets you serve the best format each browser can handle:

<picture>
  <source srcset="photo.avif" type="image/avif">
  <source srcset="photo.webp" type="image/webp">
  <img src="photo.jpg" alt="Description" width="800" height="600">
</picture>

This progressive approach gives AVIF to browsers that support it, WebP to those that don’t, and JPEG as the universal fallback. It’s more work upfront — you’re generating three versions of every image — but the bandwidth savings are substantial. For a detailed walkthrough of WebP implementation specifically, see our WebP conversion guide.

Print vs Digital: Two Completely Different Worlds

Here’s a mistake I’ve watched people make over and over: optimizing images for the web and then sending those same files to a print shop. Or, conversely, sending the print shop’s massive TIFFs to their web developer and wondering why the site loads like it’s 1998.

Print demands maximum quality and specific color profiles. TIFF and high-quality JPEG (95-100%) are standard. Print resolution is typically 300 DPI, which means a standard letter-size image needs to be roughly 2550x3300 pixels. File sizes of 20-100 MB per image are normal and expected. Color should be in CMYK, not RGB, because printing inks work differently than screen pixels.

Digital/web demands minimum file size with acceptable quality. WebP and JPEG at 75-85% quality are standard. Resolution is measured in pixels, not DPI, and most web images are under 2000 pixels wide. Target file sizes of 50-500 KB are typical. Color is always RGB.

The format implications are clear:

Use Case	Recommended Format	Quality	Color Space	Typical File Size
Web hero image	WebP or JPEG	80-85%	sRGB	100-300 KB
Product photo (web)	WebP or JPEG	80-85%	sRGB	50-200 KB
Social media	JPEG or PNG	85-90%	sRGB	200-500 KB
Magazine print	TIFF	Lossless	CMYK	20-100 MB
Large format print	TIFF	Lossless	CMYK	50-500 MB
Archival storage	TIFF or PNG	Lossless	Original	10-100 MB

The workflow that makes sense: always archive your master files in a lossless format (TIFF or PNG). Generate web-optimized versions from those masters whenever needed. This way you never lose quality and you can always re-export at different settings.

Batch Conversion That Doesn’t Make You Want to Quit

Converting one image is trivial. Converting a hundred is tedious. Converting a thousand is a workflow problem that demands the right tool.

I’ve tried everything over the years — command-line tools like ImageMagick (powerful but intimidating), desktop apps like IrfanView (solid but Windows-only), Photoshop batch actions (capable but absurdly slow for simple format conversion). They all work, but they all have friction that adds up when you’re dealing with large volumes regularly.

BulkImagePro for Batch Format Conversion

BulkImagePro’s converter tool is built specifically for this. Drop in your images, pick your target format, and download the results. Everything happens in your browser, so there’s nothing to install, your files never leave your device, and it handles hundreds of images in a single batch.

Here’s my typical conversion workflow:

1. Gather source images into a single folder. Don’t mix formats randomly — group them by what you need (e.g., all HEIC photos from last week’s shoot, all PNG screenshots for the knowledge base).

2. Resize first if needed. If the source images are 4000px wide and you need them at 1200px for the web, resize before converting. BulkImagePro’s resize tool handles this in bulk. Resizing before conversion means the converter processes smaller files, which speeds things up.

3. Convert to your target format. For web delivery, that’s usually JPG to WebP or PNG to WebP. For legacy compatibility, it might be HEIC to JPG. For print prep, you’d export as TIFF from your editing software before the batch process.

4. Compress if needed. If you’ve converted to JPEG or WebP, run the results through BulkImagePro’s compressor at 80% quality to squeeze out the last bit of unnecessary file weight.

5. Verify a sample. Before uploading your entire batch, spot-check 5-10 images across different types (photos vs. graphics, light vs. dark, detail-heavy vs. simple). Make sure the conversion looks right at full size.

This entire workflow — resize, convert, compress, verify — takes maybe ten minutes for a few hundred images. Compare that to the hours you’d spend processing them individually in Photoshop or battling ImageMagick command-line syntax.

When You Need Something More Programmatic

If you’re a developer building format conversion into an automated pipeline, you’ll probably reach for Sharp (Node.js) or Pillow (Python). These libraries give you full control over encoding parameters, support scripting, and integrate into CI/CD workflows. But for the vast majority of people who just need to convert a batch of images and move on with their day, a browser-based tool like BulkImagePro is faster and simpler.

The Format That’s Eating the Web

Let’s talk about WebP and AVIF, because they’re reshaping how images work online, and the shift is happening faster than most people realize.

WebP: The New Default

Google released WebP back in 2010, but it took more than a decade to reach critical mass. Safari was the holdout — it didn’t add WebP support until version 16 in September 2022. That single browser was the reason most developers couldn’t justify WebP as a primary format for years.

Now, with 97%+ global support, WebP is effectively the new JPEG. It does everything JPEG does but with 25-35% smaller files. It does everything PNG does (including transparency) but smaller. It even handles animation, making it a viable GIF replacement with massively better compression and full color support.

The practical gains are significant. I recently converted a client’s entire blog image library — about 400 images — from JPEG to WebP. Total storage dropped from 180 MB to 118 MB. Page load times improved across the board. And every single image looked identical to the original at normal viewing size.

If you’re still serving JPEG as your primary format in 2026, you’re leaving performance on the table. Our WebP conversion guide walks through the full transition process, including generating fallbacks for the last few browsers that don’t support it.

AVIF: The Next Wave

AVIF takes the efficiency gains further — roughly 50% smaller than JPEG and about 20% smaller than WebP at equivalent perceived quality. It’s based on the AV1 video codec, which means it benefits from the massive engineering investment that went into making video streaming more efficient.

The adoption curve is following WebP’s pattern, just a few years behind. Chrome led the way in 2020, Firefox followed in 2021, Safari added support in 2023, and Edge came along in 2024. At ~93% global support, AVIF is past the tipping point where early adopters should be using it, but it’s not yet at the “use it as your only format” stage.

The practical barrier with AVIF is encoding speed. Converting a batch of images to AVIF takes 5-10 times longer than converting to WebP or JPEG. For a quick batch of 50 images, the difference is negligible. For a catalog of 10,000 product images, it’s the difference between a coffee break and an overnight process.

My recommendation: use AVIF as the primary source in <picture> elements with WebP and JPEG fallbacks. If that level of multi-format management feels like too much work for your site, just go with WebP — you’ll capture most of the efficiency gains with less complexity. For a deeper comparison of these next-gen formats, read our HEIF and AVIF image formats overview.

The Conversion Mistakes That Keep Coming Back

After years of converting images — my own and clients’ — I’ve seen the same mistakes repeat themselves. Here’s what to watch for so you don’t learn these lessons the hard way.

Mistake 1: Converting Lossy to Lossy Repeatedly

Every lossy-to-lossy conversion degrades quality. JPEG to WebP? One generation of loss. Then WebP back to JPEG because a platform requires it? Two generations. Then that JPEG gets compressed again on upload? Three. By now, you can probably see the artifacts without zooming in.

The fix: Always convert from your highest-quality source. Keep originals in lossless formats. If you only have a JPEG, convert directly to your final target format — don’t bounce through intermediaries.

Mistake 2: Converting Photographs to PNG

I cannot tell you how many times I’ve seen someone save a 4000x3000 photograph as PNG “because PNG is higher quality.” Yes, PNG is lossless. But a photograph saved as PNG will be 15-30 MB when the same image as an 85% JPEG is 500 KB — and the visual difference is undetectable at normal viewing conditions.

The fix: Use PNG for graphics with sharp edges, text, and transparency. Use JPEG or WebP for photographs. Always.

Mistake 3: Ignoring Color Profile Conversion

This one bites print designers regularly. Your monitor displays images in RGB. Printers use CMYK. If you convert a file’s format without also converting its color profile for the intended output, the printed colors won’t match what you see on screen. Bright reds go muddy, vivid blues shift green, and your client is unhappy.

The fix: Handle color profile conversion in your editing software (Photoshop, Affinity Photo, GIMP) before batch format conversion. Convert RGB to CMYK for print, ensure sRGB for web.

Mistake 4: Not Testing Across Devices

A format that looks perfect on your Retina MacBook Pro might look completely different on your customer’s budget Android phone or your boss’s ancient Dell monitor. Different screens render colors and compression artifacts differently.

The fix: Test converted images on at least three devices: your primary screen, a mobile device, and whatever represents your “worst case” audience hardware.

Mistake 5: Forgetting About Metadata

Format conversion can strip EXIF metadata — camera settings, GPS coordinates, copyright information, color profiles. Sometimes that’s desirable (stripping GPS data for privacy). Sometimes it’s catastrophic (losing copyright info from a professional photographer’s portfolio).

The fix: Decide upfront whether you need to preserve metadata and choose your conversion tool accordingly. Most batch tools offer a metadata preservation option.

Mistake 6: Using BMP or TIFF for Web Delivery

It sounds obvious, but I’ve audited sites that were serving TIFF files directly. A single uncompressed TIFF on a product page can weigh more than the entire rest of the page combined. Browsers that can’t display TIFF just show a broken image icon.

The fix: Always convert to a web-safe format (JPEG, PNG, WebP, or AVIF) before uploading to any website or web application. Use BulkImagePro’s converter to handle this in bulk.

Your Format Conversion Cheat Sheet

When all the details get overwhelming, here’s the decision framework I come back to every time:

Starting with HEIC files? Convert to JPEG for maximum compatibility or WebP for web delivery. Use BulkImagePro’s HEIC converter.

Starting with TIFF files? Convert to JPEG or WebP for web, keep TIFF originals for print and archival. See our TIFF format guide.

Starting with BMP files? Convert to literally anything else. PNG for lossless, JPEG for photos, WebP for web delivery. Our BMP conversion guide covers every path.

Starting with JPEG and need smaller files? Convert to WebP with BulkImagePro’s JPG to WebP converter for 25-35% savings at the same quality.

Starting with PNG and need smaller files? If the images are photos, convert to WebP or JPEG. If they’re graphics that need transparency, convert to WebP with PNG to WebP.

Need to create web-ready versions from any format? Run everything through BulkImagePro’s converter and select WebP as the output. Then compress at 80% quality with the compressor tool for the best balance of size and quality.

Ready to convert your images? BulkImagePro’s free converter tool handles batch conversion between JPEG, PNG, WebP, GIF, BMP, TIFF, and HEIC — directly in your browser with no uploads, no installs, and no file limits. Drop in your images and download the converted results in seconds.

Frequently Asked Questions

Does converting an image format reduce quality?

It depends on the conversion. Converting from a lossless format (PNG, TIFF) to another lossless format preserves quality perfectly. Converting from lossless to lossy (e.g., PNG to JPEG) introduces some quality loss, but at 80-85% quality settings the difference is typically invisible. Converting from lossy to lossy (e.g., JPEG to WebP) adds another generation of compression, though modern encoders minimize this. The key rule: always convert from your highest-quality source file, and avoid chaining multiple lossy conversions.

What is the best image format for websites in 2026?

WebP is the best general-purpose format for websites in 2026. It delivers 25-35% smaller files than JPEG, supports transparency and animation, and works in 97%+ of browsers. For sites that want maximum compression, AVIF offers roughly 50% savings over JPEG with ~93% browser support. The ideal approach is serving AVIF with WebP fallback and JPEG as a final safety net using the HTML picture element.

How do I convert HEIC photos to JPEG or PNG?

The easiest way is to use a browser-based converter like BulkImagePro. Go to the HEIC to JPG converter, drop in your HEIC files, and download the JPEG versions. No software installation needed, and it handles hundreds of files at once. On iPhone, you can also change the camera settings (Settings > Camera > Formats > Most Compatible) to shoot in JPEG directly, but this won't help with photos you've already taken in HEIC.

Can I convert images in bulk without installing software?

Yes. BulkImagePro runs entirely in your browser and handles batch format conversion for hundreds of images at once. Your files never leave your device -- all processing happens locally using your browser's built-in capabilities. Just drag and drop your images, select the target format, and download the results. It supports conversion between JPEG, PNG, WebP, GIF, BMP, TIFF, and HEIC.

Should I convert my JPEG images to WebP?

In most cases, yes. Converting JPEG to WebP typically reduces file sizes by 25-35% at the same visual quality, which directly improves page load times and user experience. The only reasons to hold off are if your audience uses very old browsers (pre-2019) that don't support WebP, or if you're uploading to a platform that specifically requires JPEG. For websites you control, WebP should be your default format.

What's the difference between HEIC and JPEG?

HEIC (High Efficiency Image Container) produces files roughly 40-50% smaller than JPEG at equivalent visual quality, and it supports features JPEG lacks like transparency, depth maps, and image sequences. Apple adopted HEIC as the default iPhone camera format for these efficiency gains. The major downside is compatibility -- HEIC has very limited support outside the Apple ecosystem, which is why most people need to convert HEIC to JPEG or WebP for sharing, web use, or printing.